The present invention is related to a transmission, and more particularly to a fully engaged transmission.
Following fast economic development in recent years, the buying of a car to serve as a means of transportation is no longer a luxury. Every car driver knows that it is easier to drive a car with an automatic shift than a car with a manual shift. In driving a car with a manual shift, the driver, during every gear shifting procedure, must release the accelerator and step on the clutch, and then, step on the accelerator and release the clutch after the gear shifting lever is properly shifted in. The gear shifting procedure requires six sequential movements. Therefore, when the gear shifting procedure is repeatedly performed in a crowded street, a driver will naturally become oblivious to danger. Moreover, the accelerator must be released when shifting, and therefore the speed of the car is reduced, causing a loss of power. While climbing a hill, if the gear is not properly shifted, engine stalling may result. Because the gear shifting procedure is complicated, the driver is often disinclined to shift so that the car engine may be operated at improper speed so as to increase fuel consumption or possibly damage the engine. As a consequence, incomplete combustion of fuel deteriorates the quality of the air. The above problems will not be encountered while driving a car having an automatic shift. However, an automatic shift transmission is very complicated and expensive to manufacture and maintain, generally comprising planetary gear set, clutch brake device and control devices. Therefore, the power consumption of the automatic shift transmission is 18% greater than that of manual shift transmission.
Conventional automatic shift transmissions and manual shift transmissions can not meet the present requirements, so continuously variable transmissions (CVT) have been successfully developed and first applied in the cars of the model Justy manufactured by Subaru Japan. This kind of transmission has two points of advantage, one of which is that the structure is very compact and simple, the other of which is that the engine can provide maximum performance at an given engine speed. However, there are two points of disadvantage. The first one is that tardiness of speed change may require the operator to sometimes violently step on the accelerator to shift, and the second one is that the chain of power transmission is clipped by the pulley.
Nowadays, the excessive consumption of energy and damage to the environment are problems associated with the automobile. Thus, a kind of engine with low fuel consumption and reduced air pollution is a world-wide development goal; also a kind of fully engaged transmission is necessary to urge the development.